[PATCH] mtd: rawnand: mtk: fix object reference leaks in mtk_ecc_get

[PATCH] mtd: rawnand: mtk: fix object reference leaks in mtk_ecc_get

[wen yang]

of_find_device_by_node() takes a reference to the struct device
when it finds a match via get_device, there is no need to call
get_device() twice.
We also should make sure to drop the reference to the device
taken by of_find_device_by_node() on driver unbind.

Fixes: 1d6b1e464950 ("mtd: mediatek: driver for MTK Smart Device")
Signed-off-by: Wen Yang <yellowriver2010@hotmail.com>
Suggested-by: Boris Brezillon <bbrezillon@kernel.org>
Cc: Xiaolei Li <xiaolei.li@mediatek.com>
Cc: Boris Brezillon <bbrezillon@kernel.org>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: linux-mtd@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mediatek@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
 drivers/mtd/nand/raw/mtk_ecc.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/raw/mtk_ecc.c b/drivers/mtd/nand/raw/mtk_ecc.c
index 6432bd7..25bdc15 100644
--- a/drivers/mtd/nand/raw/mtk_ecc.c
+++ b/drivers/mtd/nand/raw/mtk_ecc.c
@@ -265,17 +265,25 @@ static struct mtk_ecc *mtk_ecc_get(struct device_node *np)
 {
 	struct platform_device *pdev;
 	struct mtk_ecc *ecc;
+	int ret;
 
 	pdev = of_find_device_by_node(np);
-	if (!pdev || !platform_get_drvdata(pdev))
+	if (!pdev)
 		return ERR_PTR(-EPROBE_DEFER);
+	if (!platform_get_drvdata(pdev)) {
+		ret = -EPROBE_DEFER;
+		goto err_put_device;
+	}
 
-	get_device(&pdev->dev);
 	ecc = platform_get_drvdata(pdev);
 	clk_prepare_enable(ecc->clk);
 	mtk_ecc_hw_init(ecc);
 
 	return ecc;
+
+err_put_device:
+	put_device(&pdev->dev);
+	return ERR_PTR(ret);
 }
 
 struct mtk_ecc *of_mtk_ecc_get(struct device_node *of_node)
-- 
2.7.4


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Re: [PATCH] mtd: rawnand: mtk: fix object reference leaks in mtk_ecc_get

[Miquel Raynal]

Hi wen,

wen yang <yellowriver2010@hotmail.com> wrote on Tue, 5 Feb 2019
10:05:46 +0000:

> of_find_device_by_node() takes a reference to the struct device
> when it finds a match via get_device, there is no need to call
> get_device() twice.
> We also should make sure to drop the reference to the device
> taken by of_find_device_by_node() on driver unbind.
> 
> Fixes: 1d6b1e464950 ("mtd: mediatek: driver for MTK Smart Device")
> Signed-off-by: Wen Yang <yellowriver2010@hotmail.com>
> Suggested-by: Boris Brezillon <bbrezillon@kernel.org>
> Cc: Xiaolei Li <xiaolei.li@mediatek.com>
> Cc: Boris Brezillon <bbrezillon@kernel.org>
> Cc: Miquel Raynal <miquel.raynal@bootlin.com>
> Cc: Richard Weinberger <richard@nod.at>
> Cc: David Woodhouse <dwmw2@infradead.org>
> Cc: Brian Norris <computersforpeace@gmail.com>
> Cc: Marek Vasut <marek.vasut@gmail.com>
> Cc: Matthias Brugger <matthias.bgg@gmail.com>
> Cc: linux-mtd@lists.infradead.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-mediatek@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> ---
>  drivers/mtd/nand/raw/mtk_ecc.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/mtk_ecc.c b/drivers/mtd/nand/raw/mtk_ecc.c
> index 6432bd7..25bdc15 100644
> --- a/drivers/mtd/nand/raw/mtk_ecc.c
> +++ b/drivers/mtd/nand/raw/mtk_ecc.c
> @@ -265,17 +265,25 @@ static struct mtk_ecc *mtk_ecc_get(struct device_node *np)
>  {
>  	struct platform_device *pdev;
>  	struct mtk_ecc *ecc;
> +	int ret;
>  
>  	pdev = of_find_device_by_node(np);
> -	if (!pdev || !platform_get_drvdata(pdev))
> +	if (!pdev)
>  		return ERR_PTR(-EPROBE_DEFER);
> +	if (!platform_get_drvdata(pdev)) {
> +		ret = -EPROBE_DEFER;
> +		goto err_put_device;
> +	}
>  
> -	get_device(&pdev->dev);
>  	ecc = platform_get_drvdata(pdev);
>  	clk_prepare_enable(ecc->clk);
>  	mtk_ecc_hw_init(ecc);
>  
>  	return ecc;
> +
> +err_put_device:
> +	put_device(&pdev->dev);
> +	return ERR_PTR(ret);

Same as before, I don't think a label is useful in this situation.


Thanks,
Miquèl

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